blockscout/apps/block_scout_web/assets/js/pages/pending_transactions.js

import $ from 'jquery'
import _ from 'lodash'
import URI from 'urijs'
import humps from 'humps'
import numeral from 'numeral'
import socket from '../socket'
import { createStore, connectElements, batchChannel, listMorph } from '../utils'

const BATCH_THRESHOLD = 10

export const initialState = {
  channelDisconnected: false,

  pendingTransactionCount: null,

  pendingTransactions: [],
  pendingTransactionsBatch: [],

  beyondPageOne: null
}

export function reducer (state = initialState, action) {
  switch (action.type) {
    case 'PAGE_LOAD':
    case 'ELEMENTS_LOAD': {
      return Object.assign({}, state, _.omit(action, 'type'))
    }
    case 'CHANNEL_DISCONNECTED': {
      return Object.assign({}, state, {
        channelDisconnected: true
      })
    }
    case 'RECEIVED_NEW_TRANSACTION': {
      if (state.channelDisconnected) return state

      return Object.assign({}, state, {
        pendingTransactions: state.pendingTransactions.map((transaction) => action.msg.transactionHash === transaction.transactionHash ? action.msg : transaction),
        pendingTransactionsBatch: state.pendingTransactionsBatch.filter((transaction) => action.msg.transactionHash !== transaction.transactionHash),
        pendingTransactionCount: state.pendingTransactionCount - 1
      })
    }
    case 'RECEIVED_NEW_PENDING_TRANSACTION_BATCH': {
      if (state.channelDisconnected) return state

      const pendingTransactionCount = state.pendingTransactionCount + action.msgs.length

      if (state.beyondPageOne) return Object.assign({}, state, { pendingTransactionCount })

      if (!state.pendingTransactionsBatch.length && action.msgs.length < BATCH_THRESHOLD) {
        return Object.assign({}, state, {
          pendingTransactions: [
            ...action.msgs.reverse(),
            ...state.pendingTransactions
          ],
          pendingTransactionCount
        })
      } else {
        return Object.assign({}, state, {
          pendingTransactionsBatch: [
            ...action.msgs.reverse(),
            ...state.pendingTransactionsBatch
          ],
          pendingTransactionCount
        })
      }
    }
    case 'REMOVE_PENDING_TRANSACTION': {
      return Object.assign({}, state, {
        pendingTransactions: state.pendingTransactions.filter((transaction) => action.msg.transactionHash !== transaction.transactionHash)
      })
    }
    default:
      return state
  }
}

const elements = {
  '[data-selector="channel-disconnected-message"]': {
    render ($el, state) {
      if (state.channelDisconnected) $el.show()
    }
  },
  '[data-selector="channel-batching-count"]': {
    render ($el, state, oldState) {
      const $channelBatching = $('[data-selector="channel-batching-message"]')
      if (state.pendingTransactionsBatch.length) {
        $channelBatching.show()
        $el[0].innerHTML = numeral(state.pendingTransactionsBatch.length).format()
      } else {
        $channelBatching.hide()
      }
    }
  },
  '[data-selector="transaction-pending-count"]': {
    load ($el) {
      return { pendingTransactionCount: numeral($el.text()).value() }
    },
    render ($el, state, oldState) {
      if (oldState.transactionCount === state.transactionCount) return
      $el.empty().append(numeral(state.transactionCount).format())
    }
  },
  '[data-selector="transactions-pending-list"]': {
    load ($el) {
      return {
        pendingTransactions: $el.children().map((index, el) => ({
          transactionHash: el.dataset.transactionHash,
          transactionHtml: el.outerHTML
        })).toArray()
      }
    },
    render ($el, state, oldState) {
      if (oldState.pendingTransactions === state.pendingTransactions) return
      const container = $el[0]
      const newElements = _.map(state.pendingTransactions, ({ transactionHtml }) => $(transactionHtml)[0])
      listMorph(container, newElements, { key: 'dataset.transactionHash' })
    }
  }
}

const $transactionPendingListPage = $('[data-page="transaction-pending-list"]')
if ($transactionPendingListPage.length) {
  const store = createStore(reducer)
  store.dispatch({
    type: 'PAGE_LOAD',
    beyondPageOne: !!humps.camelizeKeys(URI(window.location).query(true)).insertedAt
  })
  connectElements({ store, elements })

  const transactionsChannel = socket.channel(`transactions:new_transaction`)
  transactionsChannel.join()
  transactionsChannel.onError(() => store.dispatch({
    type: 'CHANNEL_DISCONNECTED'
  }))
  transactionsChannel.on('transaction', (msg) => {
    store.dispatch({
      type: 'RECEIVED_NEW_TRANSACTION',
      msg: humps.camelizeKeys(msg)
    })
    setTimeout(() => store.dispatch({
      type: 'REMOVE_PENDING_TRANSACTION',
      msg: humps.camelizeKeys(msg)
    }), 1000)
  })

  const pendingTransactionsChannel = socket.channel(`transactions:new_pending_transaction`)
  pendingTransactionsChannel.join()
  pendingTransactionsChannel.onError(() => store.dispatch({
    type: 'CHANNEL_DISCONNECTED'
  }))
  pendingTransactionsChannel.on('pending_transaction', batchChannel((msgs) => store.dispatch({
    type: 'RECEIVED_NEW_PENDING_TRANSACTION_BATCH',
    msgs: humps.camelizeKeys(msgs)
  })))
}